Atomic layer deposition of InN using trimethylindium and ammonia plasma

Abstract

InN is a low band gap, high electron mobility semiconductor material of interest to optoelectronics and telecommunication. Such applications require the deposition of uniform crystalline InN thin films on large area substrates, with deposition temperatures compatible with this temperature-sensitive material. As conventional chemical vapor deposition (CVD) struggles with the low temperature tolerated by the InN crystal, we hypothesize that a time-resolved, surface-controlled CVD route could offer a way forward for InN thin film deposition. In this work, we report atomic layer deposition of crystalline, wurtzite InN thin films using trimethylindium and ammonia plasma on Si(100). We found a narrow ALD window of 240-260 °C with a deposition rate of 0.36 Å/cycle and that the flow of ammonia into the plasma is an important parameter for the crystalline quality of the film. X-ray diffraction measurements further confirmed the polycrystalline nature of InN thin films. X-ray photoelectron spectroscopy measurements show nearly stoichiometric InN with low carbon level (< 1 atomic %) and oxygen level (< 5 atomic %) in the film bulk. The low carbon level is attributed to a favorable surface chemistry enabled by the NH3 plasma. The film bulk oxygen content is attributed to oxidation upon exposure to air via grain boundary diffusion and possibly by formation of oxygen containing species in the plasma discharge.

Epitaxial GaN using Ga(NMe2)3 and NH3 plasma by atomic layer deposition

“…The NH 3 (AGA/Linde, 99.999%) plasma used as the nitrogen source was an Ar (99.999%, further purified with a getter filter to remove moisture)/ NH 3 (100/75 sccm) mixture, ignited using a plasma power of 2800 W. These plasma parameters was previously investigated to be optimal for our reactor and deposition of nitrides. 25 A plasma pulse of 9 s followed by a 10 s purge was used with the above parameters unless otherwise stated. The thickness of the GaN film was 70 nm unless otherwise stated.…”

Epitaxial GaN using Ga(NMe2)3 and NH3 Plasma by Atomic Layer Deposition

“…The NH3 (AGA/Linde, 99.999 %) plasma used as the nitrogen source was an Ar (99.999 %, further purified with a getter filter to remove moisture)/NH3 (100/75 sccm) mixture, ignited using a plasma power of 2800 W. These plasma parameters was previously investigated to be optimal for our reactor and deposition of nitrides. 25 A plasma pulse of 9 s followed by a 10 s purge was used with the above parameters unless otherwise stated. The thickness of the GaN film was 70 nm unless otherwise stated.…”

Elucidating the role of nitrogen plasma composition in the low-temperature self-limiting growth of indium nitride thin films

“…33,34 To date, there have been multiple efforts towards low-temperature InN growth via PE-ALD. 17,[30][31][32][35][36][37][38][39][40][41] Initial epitaxial growth of InN at sub-300 C was achieved by plasma-enhanced atomic layer epitaxy (PE-ALE) where the lms exhibited substrate-dependent varying crystallographic orientations. 17,36 In a relatively recent study, PE-ALD of monocrystalline InN lms has also been reported at 250 C using N 2 -plasma on lower-lattice-mismatched ZnO/Al 2 O 3 substrates, where the lms were fully relaxed with no voids or interlayers at the interfaces.…”

“…17,36 In a relatively recent study, PE-ALD of monocrystalline InN lms has also been reported at 250 C using N 2 -plasma on lower-lattice-mismatched ZnO/Al 2 O 3 substrates, where the lms were fully relaxed with no voids or interlayers at the interfaces. 31 Moreover, Pedersen et al have recently employed NH 3 -plasma to grow crystalline InN lms 38,39 via PE-ALD, despite its adverse environmental impacts and corrosivity. Majority of the studies around PE-ALD deposition of InN report on single-phase h-InN lms when using hydrogen-free nitrogen plasmas, whereas addition of H 2 to the plasma gas has resulted in degraded lm quality with elevated impurity content and even lm porosity.…”